With a current population of 55,197, Towson is the seat of Baltimore County and the second-most populated unincorporated county seat in the U.S. In 1967, a 15-story office high-rise was built in the heart of downtown Towson to house multiple prominent investment firms. With 13 floors of office space and two floors of garage, it most recently accomodated an assortment of state and county offices until it was closed in 2002 and declared a sick building due to alleged ventilation issues.
The building stood vacant for 10 years until Caves Valley Partners (CVP), a Towson-based real estate development firm acquired the building and set about planning an extreme makeover reusing the existing steel and concrete structure with a state-of-the-art modernization program to bring it up to code and make it a high-quality, Class A office building. The renovation included a new glass curtain wall façade and replacement of the mechanical and electrical systems. Today, the sparkling, 170,000-square-foot, LEED® Silver certified tower is fully leased and home to the Towson University Institute for Well Being and MileOne Automotive.
Challenge: Finding an HVAC system that would maximize the ceiling height while earning LEED points.
To undertake this challenging makeover, CVP turned to Chesapeake Contracting Group of Reisterstown, Md., and Brasher Architects of Columbia, Md. They decided the best fit for this type of renovation was the engineers of the Baltimore design/build firm Mechanical Engineering & Construction Corporation (MEC2), Baltimore.
President of Brasher Architects, D. Ronald Brasher, AIA, said, “Towson City Center was the most challenging renovation project in my 30-year career. Nothing was as it should have been or as one would expect it to be and nothing was square, as disclosed when the glazing contractor called as he was installing the 12-story curtain wall system and informed us that the building was out of plumb horizontally and vertically with as much as two inches in some areas.”
Steve Wagner, MEC2s director of engineering, and Principal Rich Beattie stated the scope of work included gutting the entire tower, keeping only the structural steel, slabs and elevator core. When selecting a new HVAC system for the space, Wagner said that one of the team’s many challenges was the low deck height of the original design. Instead of a typical 14-foot space between floors, the 12 floor slabs measured only 10-feet-6-inches, allowing less than nine feet of clearance below the existing structure. This already low ceiling height meant that an HVAC solution that required significant ductwork was off the table.
Another factor to consider was selecting an HVAC system that would help the building earn LEED points. “From day one, we all worked with our sights set on achieving LEED certification,” Wagner said. “This meant selecting the best HVAC system for the tower that would deal with the difficult low decks and also help us succeed in meeting the critical environment and indoor air quality standards demanded by the U.S. Green Building Council.”
Wagner explained that the team ultimately selected a Mitsubishi Electric Cooling & Heating Variable Refrigerant Flow (VRF) zoning system, which helped the design team meet the many challenges posed by this building.
VRF Zoning Flexibility Paramount
“Because Mitsubishi’s multi-port controller makes the system so flexible, we were able to easily orchestrate the piping and wiring for each floor,” Wagner said. “It is so much easier and less costly to install, that individual zoning becomes immediately available. When a building is not yet leased and there is no interior tenant improvement plan, this system allows you to install indoor fan coils when space becomes rented and rooms identified.”
Solution: The Mitsubishi Electric VRF zoning system helped turn a “sick” building into a LEED® Silver high-rise with a huge rebate from the local utility.
Mitsubishi Electric’s low-profile (9-7/8-inch) indoor unit fan coils helped the design team overcome the ducting height limitations posed by the low decks. Traditional fan coils can be twice as deep – 18 inches deep by 14 inches wide. Because of their small footprint and less weight, the 15 outdoor units fit nicely on the roof, freeing up the entire 12,000-square-foot 13th floor that had been the mechanical room. This area became usable storage space because the building’s original boilers and chilling tower were totally removed. Seventy percent of the shaft space needed by the outdated system was filled-in significantly increasing the leasing square footage available on each floor.
“With the complete penthouse now available, we added a water-cooled Glycol™ loop to the 13th floor in case a tenant wanted to add a data center,” Wagner said. “We also put in a dedicated outdoor air system, utilizing total energy and desiccant wheels on the removed cooling tower steel grillage, so that dehumidified, conditioned ventilation air was made available for distribution to down-stream fan coil units greatly reducing the energy demanded by each fan coil. We also added Mitsubishi Electric VRF zoning fan coils in the garage and elevator lobbies.”
Earning LEED Silver Certification and a Six Figure Utility Rebate
Wagner said that the Mitsubishi Electric VRF zoning technology delivered 11 energy points needed for the certification process. LEED Silver was also granted for the dedicated outdoor air unit, individual zone controls, CO2 monitors on each floor, sound control ventilation, removal of the old, outdated system, truing the curtain wall, adding superb glazing to the windows and insulating the entire building envelope.
In addition, the efficiency upgrades for Towson City Center resulted in a $421,999 rebate through Baltimore Gas & Electric’s Smart Energy Savers Program®, which offers incentives to buildings that make sustainable building improvements.
“In many ways, that has been the most satisfying [project of my career] because, as a team, we made [the project] work,” said Brasher. “We turned a long-standing eye-sore in the middle of town into a LEED Silver landmark of great value. The tower was immediately filled with tenants and the owner was rewarded with the largest rebate I’ve ever seen.”
Sustainability, Innovation and Smart Adaptive Reuse
Currently, Towson City Center is one of the most efficient buildings in Towson, overcoming its past as an uninhabitable nuisance.
“It held such a bad reputation no one would touch it for 10 years,” said Wagner. “Mitsubishi Electric VRF engineering totally changed the nature of this structure.”
CVP Partner Arsh Mirmiran agreed. “For over a decade, Towson had to endure the presence of this 15-story ‘sick building’ in the heart of its commercial district,” said Mirmiran. “Caves Valley Partners, in a public-private partnership with the county and state, realized that the tower needed to be reborn as a green, sustainable building in order for it to succeed. This office tower was turned into a showcase for sustainability and modernization. It is a classic example of urban adaptive reuse and was immediately recognized as such, demonstrated by a building filled with happy tenants, including CVP.”